Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Learning to love bacteria: Stanford scientist highlights bugs’ benefits

24.02.2006


Bacteria are bad. Mothers and doctors, not to mention the cleaning product industry, repeatedly warn of their dangers. But a Stanford University School of Medicine microbiologist is raising the intriguing idea that persistent bacterial and viral infections have benefits.



Stanley Falkow, PhD, the Robert W. and Vivian K. Cahill Professor in Cancer Research, is publishing his thoughts on this topic in an essay in the Feb. 24 issue of the journal Cell, in which he asks, "Is persistent bacterial infection good for your health?" The essay is based on a talk he was invited to give at Cambridge University in November.

Falkow points out that the medical community and those who fund medical research focus on curing disease. He wonders if this single-mindedness might distract researchers from appreciating the beneficial contributions of micro-organisms to the body.


"Organisms that cause disease are usually considered in the context of harm and epidemics and so on," said Falkow. "But the fact is that a great number of organisms that infect humans come in and set up housekeeping as it were. There are no clinical symptoms of anything wrong and people take the organisms with them to their graves."

It’s not that the organisms in question - such as the bacteria that cause pneumonia or meningitis - are innocuous, he said. It’s just that most of the individuals do not get disease from being infected.

The best recent example of this, said Falkow, is H. pylori. First identified only 25 years ago, the organism earned researchers last year’s Nobel Prize in Medicine or Physiology for being implicated as a cause of ulcers and stomach cancer.

As is typical in the world of microbiology, though, it’s not a simple equation: being infected = ulcers or cancer. At least 80 percent of the world’s population is infected with H. pylori yet has no overt symptoms.

What makes the study of H. pylori even more perplexing is that as such advances as clean water and pasteurization are adopted, the prevalence of H. pylori infection has declined. On the one hand, this has been accompanied by a drop in the incidence of gastric cancer and ulcers. On the other, there has been an increase in esophageal cancer. H. pylori appear to protect against cancer of the esophagus. "So that says that there might be something about persistent infection that might be protective," said Falkow.

This raises the conundrum: By messing with the microbes, are we just replacing one disease with another?

Falkow’s lab has been studying the phenomenon of persistent infection for decades, in particular with H. pylori and Salmonella. He and his colleagues have shown that when infected with these organisms, mice initially show an inflammatory response that then settles down and stays with them for the rest of their lives.

Although very few of these organisms remain in the mice, it is enough to cause the immune system to have an ongoing response. "It’s not so much that the immune system has failed," Falkow explained, "but that the organisms have manipulated the immune system in such a way that they can’t be cleared." If the infections are cleared by antibiotic intervention, the mice are highly susceptible to re-infection, and the re-infection is more likely to progress to disease than the initial infection.

Furthermore, as many infectious diseases have decreased, autoimmune diseases such as ulcerative colitis, Crohn’s disease and diabetes have increased.

"All these observations have been made without necessarily trying to pull it all together," said Falkow. "So what I tried to do in this article is to point out that the continued presence of these organisms in human society may actually be beneficial to the host and that is why they are tolerated by the immune system."

It’s an intriguing idea that requires more research in animal models. "We don’t know what to look for per se," he said. "But we can guess that since a persistently infected host is constantly having its immune system stimulated and refined, that may provide it with resistance to other things."

He wondered whether, as seen with H. pylori, humans are also unknowingly causing the disappearance of other things that have been with us for all of our evolution, and that might play some role in our health. "Could it be this that is responsible for some of the things we see such as the failure of the immune system to act appropriately?" he asked.

The only answer to date is: "It’s complicated." Instead of a persistent infection, some people get very ill from organisms such as Salmonella, H. pylori, tuberculosis and meningitis. How the immune system responds differently in individuals demands further research.

Falkow credits his colleagues for providing the fodder for his essay.

Mitzi Baker | EurekAlert!
Further information:
http://www.stanford.edu

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

Construction of practical quantum computers radically simplified

05.12.2016 | Information Technology

NASA's AIM observes early noctilucent ice clouds over Antarctica

05.12.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>